Why did you left is grammatically incorrect.
It should be:
Why did you leave?
Why did she leave?
Why did he leave?
Why did they leave?
As in someone trying to remember where they left off, "Where was I?" is correct, yes.
No, not even close. What exactly are you trying to ask?
No, "hows you" is not grammatically correct. "How are you?" is correct.
This sentence is grammatically correct. However, it would be more correct to say, "I want you to pierce my baby's ear (or ears)."
This is not grammatically correct. The correct form is 'you do not know', or the abbreviated 'you don't know'.
"I left New York for Texas" is grammatically correct.
As in someone trying to remember where they left off, "Where was I?" is correct, yes.
Yes.
The phrase "had already left" is grammatically correct. The phrase "had already been gone" is not grammatically correct.
No, the sentence should be: "The police caught the thief because he left a clue." This version is grammatically correct because it includes the article "a" before "clue," making it a complete sentence.
No, not even close. What exactly are you trying to ask?
The grammatically correct version is Do you feel any aches in any places in your body?
No, "hows you" is not grammatically correct. "How are you?" is correct.
No. It should be: They let him go from his job.
This sentence is grammatically correct. However, it would be more correct to say, "I want you to pierce my baby's ear (or ears)."
Yes, 'for free', is grammatically correct.
"Not like that" can be grammatically correct, depending on the context.